[posix] Unhandled crash in npm posix

This affects all versions of package posix. When invoking the toString method, it will fallback to 0x0 value, as the value of toString is not invokable (not a function), and then it will crash with type-check.

References

• https://nvd.nist.gov/vuln/detail/CVE-2022-21211
• https://snyk.io/vuln/SNYK-JS-POSIX-2400719
• https://github.com/advisories/GHSA-27mx-gchc-6xjp